Vehicle production techniques have continued to develop to overcome many problems such as diversification of customer demand, improvement of performance and quality, price reduction through cost reduction caused by competition, and supply expansion as well as mass production.
For example, a connecting rod, which is called a con-rod, is a component used for transferring the kinetic energy of a piston to a wheel through a crank shaft, and research for improving properties such as yield strength and tensile strength while reducing production cost of the connecting rod are ongoing.
In the connecting rod, a part connected to a piston pin is called a small end, and a part connected to a crank shaft through a crank pin is called a big end. Further, a rod part connects the small end and the big end, and is a part requiring excellent mechanical characteristics such as tensile load and compression load like the small end, and its cross section has an ‘I’ shape.
More specifically, explosion pressure formed in a cylinder of an internal combustion engine applies a large compression load to the connecting rod through a piston head longitudinally. Furthermore, because the piston moves alternately, and continuous force in the forms of tensile load and compression load is applied to the connecting rod in the longitudinal direction of the connecting rod, the connecting rod may be bent.
As a method of manufacturing the connecting rod having excellent mechanical strength such as tensile strength and compression strength, a hot forging method or a sintering forging method may be used. Here, mechanical strength may be excellent because metal flow is formed in the connecting rod manufactured by the hot forging method, but there may be a disadvantage regarding the high manufacturing cost because there may be much wasted flash and many forging processes required.
Further, the connecting rod manufactured by the sintering forging method has advantages of: lower manufacturing cost than the connecting rod manufactured by the hot forging method, very low amount of lost material because flash is not formed during the process, and no need for heat treatment for removing residual stress.
However, the big end, the small end, and the rod part constituting the connecting rod require different properties from one another, and there may be a high manufacturing cost because all of them are manufactured using expensive powder for higher stress.
Further, in the prior arts, powders are filled into a die by gravity filling, but when using different kinds of powder, there may be a problem in that they are not suitable to the object of separating and using the different kinds of powder because the powders are mixed together when the die is lowered by acceleration of gravity.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.